Sliding frequency dependent piston assembly

Abstract

a pressure chamber (300) comprising a chamber wall (301), configured to be moved by said piston (10) to change volume of said pressure chamber (300).

What is claimed is: 
     
       1. A frequency dependent piston assembly for a shock absorber comprising:
 a piston slidably disposed within a portion of cylinder, dividing volume defined within said portion of cylinder into a first chamber and a second chamber, said piston comprising a flow channel connecting said first chamber and said second chamber; 
 characterized in that said piston assembly further comprises: 
 a pressure chamber comprising a chamber wall, configured to be moved by said piston to change volume of said pressure chamber; 
 a valve assembly controlling fluid flow between said first chamber and said second chamber, 
 said valve assembly being configured for its preload to be changed by the change in volume of said pressure chamber, the throttling of fluid flow by said valve assembly being dependent on the preload of said valve assembly. 
 
     
     
       2. The piston assembly according to  claim 1 , characterized in that:
 said chamber wall is flexible. 
 
     
     
       3. The piston assembly according to  claim 1 , characterized in that:
 said chamber wall is rigid. 
 
     
     
       4. The piston assembly according to  claim 1 , characterized in that:
 said valve assembly is disposed against said piston, covering said flow channel to throttle fluid flow between said first chamber and said second chamber. 
 
     
     
       5. The piston assembly according to  claim 1 , characterized in that:
 said chamber wall is configured to be pushed by movement of said piston upon a pressure differential between said first chamber and said second chamber to reduce volume of said pressure chamber. 
 
     
     
       6. The piston assembly according to  claim 1 , characterized in that said piston assembly further comprises:
 a chamber base which limits the allowed range of movement of said chamber wall. 
 
     
     
       7. The piston assembly according to  claim 6 , characterized in that:
 said chamber base also functions as a clamping washer or clamping nut. 
 
     
     
       8. The piston assembly according to  claim 1 , characterized in that:
 said chamber wall is configured to be pulled by movement of said piston upon lower pressure in said first chamber than said second chamber to increase volume of said pressure chamber. 
 
     
     
       9. The piston assembly according to  claim 1 , characterized in that:
 said piston is attached to a rod, 
 said piston is able to move relative to said rod. 
 
     
     
       10. The piston assembly according to  claim 1 , characterized in that said piston assembly further comprises:
 an orifice disc with a flow slot which changes width from its inner diameter to outer diameter. 
 
     
     
       11. The piston assembly according to  claim 1 , characterized in that:
 said chamber wall is part of said piston. 
 
     
     
       12. The piston assembly according to  claim 1 , characterized in that said piston assembly further comprises:
 a flow restrictor to throttle fluid flow into or out of said pressure chamber. 
 
     
     
       13. The piston assembly according to  claim 12 , characterized in that:
 said flow restrictor comprises a thin orifice disc. 
 
     
     
       14. The piston assembly according to  claim 12 ,
 characterized in that: 
 said flow restrictor opens up a bigger flow cross section depending on flow direction. 
 
     
     
       15. The piston assembly according to  claim 1 , characterized in that said piston assembly further comprises:
 an elastic element configured to help said valve assembly oppose movement of said piston.